The invention relates to a process for producing a coating on the surface of plasticizing screws for injection molding machines, in which a metal, carbide-metal or ceramic material is applied with a low degree of distortion to a screw main body consisting of steel, by means of at least one spray jet using the high-speed flame spray process.
In order to improve the wear resistance of plasticizing screws, the conventional state of the art provides that the plasticizing screws are hardened or coated by means of flame spraying with subsequent heat treatment. Both can result in deformation of the screw, while in the case of flame spraying, cracks can occur in the coating in the subsequent operation of straightening the plasticizing screw. A plasticizing screw of that kind is therefore not resistant to corrosion.